[Tagging] Bad tag: demolished=<date>: move to a) modify, b) strongly discourage

[Ole Nielsen]

On 27/06/2013 19:23, Andrew Chadwick (lists) wrote:
>    iii. We should not in general be mapping features which are no
> longer physically relevant. Demolished items by their very nature are
> not relevant, and are potentially not verifiable. OSM a map of the the
> world as it is in reality, verifiably and currently, and not a
> historic map. If a demolished item is currently a brownfield site, it
> should be tagged as a new object with those details. If it's now a
> construction site, tag it as that.
>
> Therefore I propose:
>
> a) Modification of this page to avoid bad data creeping into the database, by:
>
>    1. Rewriting it as a namespace in a similar manner to abandoned and
> disused, addressing [i];

Agree, although "demolished" may not be the best choice. I use 
"removed:<key>=<value>" as it is more neutral than "demolished" which is 
mainly applicable to buildings.

>    2. Altering the date specification to be Right, namely the ISO 8601
> date formats, addressing [ii].

I use end_date=<date> (usually only the year)

>
> b) Strongly discouraging its use altogether, addressing [iii].

Disagree. There are reasons to keep objects in the DB after they have 
ceased to exist. First of all that will (hopefully) prevent other 
mappers from accidentially remapping features still visible in outdated 
imagery. Recently dismantled power lines are good examples for this as 
they are often mapped by armchair mappers. Secondly, some people may 
have a genuine interest in keeping a geographical record of disappeared 
objects, in particular significant objects that may have dominated an 
area and may be found in old photos etc. I agree we shouldn't start 
adding long gone objects to OSM. However, for recently 
demolished/dismantled features I find it justifiable to keep them in OSM 
especially if they can be mapped from current imagery or were mapped 
from previously available imagery such as yahoo.

Ole N